Process of making acetyl-cellulose plastic compositions.



UNITED 's'rx'ras PATENT caries.

WILLIAM G. LINDSAY, OF CALDWELL, NEW JERSEY, ASSIGNOB TO THE CELLULOII) COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY..

PROCESS OF MAKING ACETYL-CELLULOSE PLASTIC COMPOSITION.

Specification of Letters Patent.

Patented Sept. 26, 1916. Divided and this application filed July 10, 1915. I Serial No. 39,189.

To all whom it may concern:

Be it known that I, -WILLI M Gr. LINDSAY, a citizen of the United States, residing at Caldwell, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Processes of Making Acetyl-Cellulose Plastic Composition, of which the following is a specifica-' ing consistencies as to elasticity, stiffness, or

fluidity, depending generally upon the proportion or kind of solvents used to the amount of the original base-acetyl cellulose.

In the treatment of acetyl cellulose for the,

production of flexible or plastic compounds, I have discovered that water, methyl alcohol, and benzol in admixture form a useful and very strong solvent for acetyl cellulose of' that variety which is freely soluble in acetone.

My invention lies in the discovery that methyl alcohol, water, and benzol, when mixed in certain proportions combine to produce a liquid which is a solvent for the described variety of acetyl cellulose at ordinary room temperature, say 20 C., and that the use of this solvent under certain conditions for the manufacture of acetyl cellulose plastic compounds affords means of producing a material having great toughness, flexibility, and to a .very large extent freedom from brittleness. The qualities thus imparted to the finished material I have found further are of a permanentnature and thatthe product when thoroughly seasoned is well adapted for carving, molding, and polishing. I have also discovered that this sol vent may be employedfor the manufacture of a non-inflammable plastic composition which will possess toughness, flexibility, and freedom from brittleness to a marked de-' I gree, and this I have formed the subject of this separate application.

It could not be foretold that a mixture of water, methylalcohol and benzol would when added to an acetyl cellulose of the variety described produce a gelatinated mass,

and again it could not be foretold that the addition of paraethyltoluolsulfonamid to this mixture would produce a mass which could be rolled, pressed, and molded. On the contrary, it would be expected that a mixture of water and methyl alcohol with benzol would yield upon evaporation a residue high in benzol and water and would be useless as a solvent for acetyl cellulose. As

a matter of fact, however, I have not onlydiscovered that the water-benZol-methyl a1- cohol mixture in certain proportions is a solvent for acetyl cellulose in the cold or at ordinary room temperature, but that such mixture when used with the acetyl cellulose described and certain substances such as paraethyltoluolsulfonamid evaporates substantially unchanged with very little, if any, diminution in its solvent action ;that is, Whatever change (if any) takes place in'the composition of the mixed solvent during evaporation its use as .a solvent in the manufacture of acetyl cellulose plastics is not impaired.

I have further discovered that all of the so-called camphorsubstitutes are not equivalent in the preparation of acetyl cellulose plastic masses by means of the-herein-described mixed solvents. Triphenylphosphate, for instance, When used in. sufficient quantity, say from 25 to 30 parts, imparts non-inflammability to the resultant mass, but requires the addition of a sufliciently strong solid solvent such as paraethyltoluolsulfonamid to permit of the necessary subsequent manipulation to produce a material of the desired toughness and moldability.

In order to carry out my invention a good example of the process to be pursued is as follows: To 100 parts of acetyl cellulose of the variety described, I add from 50 to 100 produce gelatinization, but those give the by weight, of the so-called combest results with paraethyltoluolsulfonamid. At ordinary room temperature there results a more or less gelatinous mass depending upon the amount of solvent used, in which the particles of acetyl cellulose in a comparatively short time become completely agglomerated or amalgamated, losing their original shape and coalescing more or less Without the action of either heat or pressure. To 100 parts of acetyl cellulose which has been gelatinated by means of the Watermethyl alcohol-benzol mixture in the proportion of, say 60 parts, I add parts of triphenylphosphate and 20 to parts of paraethyltoluolsulfonamid. The mass is then subjected to kneading or malaxating action and after thorough incorporation of the diiferent constituents and a uniform miX- ture is obtained about 25 parts of the volatile solvents are allowed to evaporate under the action of further mixing. The product thus obtained is shaped up, rolled, and pressed into blocks for sheeting, and further finished. according to the processes Well lgnown for making nitro-cellulose-camphor compounds. 7

Having thus described my invention, What I clalm is The process of producing plastic compounds from acetyl cellulose of that variety which is freely soluble in acetone that consists in adding to such acetyl cellulose a mixed solvent consisting of water, benzol and methyl alcohol; allowing the mass to stand at ordinary room temperature until gelatinization has taken place; adding to such gelatinous mass paraethyltoluolsulfonamid and triphenyl phosphate; and mixing the ingredients and subsequently applying heat and pressure, substantially as described.

In testimony whereof Iafiix my signature.

WILLIAM G. LINDSAY. 

